Ohhhhh Nice Background with Halloween-theme feeling :3
I love dark wallpapers because they don't hurt my eyes like how too bright colors one would do normally.
I loved those trees, but I would advice you to blur some trees which are far from the character and also those crows
which are sitting on distance, to show some depth. I also liked that sun or moon? o.O It reminds me of Blood moon lol
it's done well.
And Ohohoho colored lineart! :3
Since it's your first time, and I don't want to be cruel xD I will explain which colors you should choose for coloring
outline.
First of all, when it adding colored outlines to wallpaper (not pure vector art without Background), color outlines
should blend well with both characters and Background and makes more sense. Here (sorry and please don't take it as
insult, it's just to let you know) the lines of hair, and clothes doesn't not really make sense at all. The outline of
hair is orange and there is no orange in hair at all and the back side where the hair turns purple because of shadows
the outlines should also turn purplish. Same for the line of her shorts/leg clothing, the outline has lighter color than
the inside color, which is unnatural. And No colored outline on skin? I would love to add a greyish-blueish-purplish
color like hex code #534764.
But since it's your first try it's okay I'm 1000% sure you'll do better next time. And if you ever feel not sure about
anything in vectoring process about colors etc. feel free to PM me, I will help you out. :D
Keep your good work up! :)